In the background art, in a hatchback vehicle having a back door in a rear portion of the vehicle, a rear glass of the back door generally has a small area in comparison with those in other vehicle models. In addition, almost all the region of the rear glass is occupied by a defogger. In the hatchback vehicle, it is therefore difficult to secure a region in which an antenna for AM (Amplitude Modulation) radio is disposed in the rear glass. Thus, a technique using the defogger as an antenna for AM radio has been known.
For example, when the defogger is used as an antenna for AM radio, a reception signal may leak from the defogger to a body of the vehicle, or noise from the body of the vehicle may be mixed into the reception signal. Therefore, when the defogger is used as an antenna for AM radio, a choke coil is used for blocking a signal in a frequency band of AM radio between the body of the vehicle and the defogger (for example, see Patent Document 1).
Patent Document 1: JP-A-2015-56716